Methods and apparatus for improving network communication using BFD and VRRP tracking system

ABSTRACT

An apparatus and method of a network system between a host and a group of routers using virtual router redundancy protocol (“VRRP”) messages and bidirectional forwarding detection (“BFD”) sessions are disclosed. The network system is capable of facilitating a first communication between a host and a master router of multiple VRRP routers and establishing a BFD session between the host and the master router. When the BFD session fails, the priority of the master router is subsequently lowered and a backup router is activated. In one embodiment, the backup router capable of performing functions of the master router becomes a new master until the BFD session resumes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of an earlier filed U.S.provisional application Ser. No. 61/188,973, filed on Aug. 14, 2008.

FIELD

The exemplary embodiment(s) of the present invention relates tocommunications network. More specifically, the exemplary embodiment(s)of the present invention relates to improve network performanceemploying BFD and VRRP tracking system.

BACKGROUND

A high-speed network environment typically includes network devices suchas routers and bridges used for facilitating delivery of informationpackets and/or data traffic from source devices to destination devices.Information pertaining to the transfer of packet(s) through the networkis usually embedded within the packet itself. Each packet travelingthrough one or more communications networks such as Internet and/orEthernet can typically be handled independently from other packets in apacket stream or traffic. For example, each router which may includerouting, switching, and/or bridging engines processes incoming packetsand determines where the packet(s) should be forwarded.

In a high-speed computing network environment, it is critical tomaintain high speed traffic flows with minimal data loss and/or packetdrop. As such, it is important to detect failures relating to data linksand/or connections between the network devices, thereby the trafficflows can be maintained and rerouted for reducing packet drop(s). Aproblem associated with a high-speed computing network is data (orpacket) loss due to data connection(s) (or data link) failure. A causeof data loss is to continue sending the data packets to a router over adata link after the data link is already down.

A conventional detecting method such as Virtual Circuit ConnectivityVerification (“VCCV”) channel over a pseudowire (“PW”) has been employedto enhance the network reliability. For example, inband VCCV channelimplemented using an MPLS PW control word (CW) may increase the abilityof the network operator to understand the status of each individual PWon an end-to-end basis across the network. Virtual Router RedundancyProtocol (“VRRP”) is another widely used method to detect linkfailure(s). VRRP, however, is typically not reliable to protectend-to-end service by VRRP routers when end user is not connected on thesame LAN segment as the VRRP routers.

A problem associated with the conventional approach(s) is that thedetection is not quick enough to stop or reroute data packets away froma down link.

SUMMARY

An apparatus and method of a network system providing a communicationbetween a host and a group of routers using a Virtual Router RedundancyProtocol (“VRRP”) tracking mechanism and Bidirectional ForwardingDetection (“BFD”) sessions are disclosed. The network system is capableof facilitating a first communication between a host and a master routerof the group of VRRP routers and establishing a BFD session between thehost and the master router. When the BFD session fails, the priority ofthe master router is lowered and a backup router is activated. In oneembodiment, the backup router capable of performing the functions ofmaster router becomes a new master until the BFD session resumes.

Additional features and benefits of the exemplary embodiment(s) of thepresent invention will become apparent from the detailed description,figures and claims set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

The exemplary embodiment(s) of the present invention will be understoodmore fully from the detailed description given below and from theaccompanying drawings of various embodiments of the invention, which,however, should not be taken to limit the invention to the specificembodiments, but are for explanation and understanding only.

FIG. 1 is a block diagram illustrating a computer network having amaster router and backup routers in accordance with one embodiment ofthe present invention;

FIG. 2 is a block diagram illustrating an exemplary computer networkhaving multiple VRRP routers managed by BFD and VRRP in accordance withone embodiment of the present invention;

FIG. 3 is a block diagram illustrating an exemplary process ofidentifying session failure by BFD in accordance with one embodiment ofthe present invention;

FIG. 4 is a diagram illustrating an exemplary process of switchingrouting path upon detecting session failure in accordance with oneembodiment of the present invention;

FIG. 5 is a diagram illustrating an exemplary process of sessionrecovery in accordance with one embodiment of the present invention;

FIG. 6 is a diagram illustrating an exemplary process of data linkrecovery in accordance with one embodiment of the present invention;

FIG. 7 is a block diagram illustrating an exemplary network layouthaving multiple VRRP routers in accordance with one embodiment of thepresent invention; and

FIG. 8 is a flowchart illustrating a process capable of activating abackup router using a connectivity protocol in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION

Exemplary embodiment(s) of the present invention is described herein inthe context of a method, device, and apparatus of improving networkperformance using Virtual Router Redundancy Protocol (“VRRP”) andBidirectional Forwarding Detection (“BFD”) tracking system.

Those of ordinary skills in the art will realize that the followingdetailed description of the exemplary embodiment(s) is illustrative onlyand is not intended to be in any way limiting. Other embodiments willreadily suggest themselves to such skilled persons having the benefit ofthis disclosure. Reference will now be made in detail to implementationsof the exemplary embodiment(s) as illustrated in the accompanyingdrawings. The same reference indicators will be used throughout thedrawings and the following detailed description to refer to the same orlike parts.

In the interest of clarity, not all of the routine features of theimplementations described herein are shown and described. It will, ofcourse, be understood that in the development of any such actualimplementation, numerous implementation-specific decisions may be madein order to achieve the developer's specific goals, such as compliancewith application- and business-related constraints, and that thesespecific goals will vary from one implementation to another and from onedeveloper to another. Moreover, it will be understood that such adevelopment effort might be complex and time-consuming, but wouldnevertheless be a routine undertaking of engineering for those ofordinary skills in the art having the benefit of embodiment(s) of thisdisclosure.

Various embodiments of the present invention illustrated in the drawingsmay not be drawn to scale. Rather, the dimensions of the variousfeatures may be expanded or reduced for clarity. In addition, some ofthe drawings may be simplified for clarity. Thus, the drawings may notdepict all of the components of a given apparatus (e.g., device) ormethod.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skills in the art to which the exemplary embodiment(s)belongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand this exemplary embodiment(s) of the disclosure.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. The term “and/or” includes any andall combinations of one or more of the associated listed items

Embodiments of the present invention illustrate a network systemconfigured to enhance network performance using a VRRP trackingmechanism and BFD session(s). The network system is capable offacilitating a data communication between a host and a master routerwhich, for example, is one of the VRRP routers with the highestpriority. In addition, a BFD session between the host and the masterrouter is formed to verify connectivity between the host and the masterrouter. Upon detecting the failure of the BFD session, the priority ofthe master router is lowered via the VRRP tracking mechanism. A backuprouter is subsequently activated in response to the VRRP trackingmechanism. In one embodiment, the backup router subsequently becomes thenew master router until the BFD session is reestablished.

FIG. 1 is a block diagram 100 illustrating a computer network having amaster router and a backup router in accordance with one embodiment ofthe present invention. Diagram 100 includes multiple cell sites 102-103,a switching network 104, multiple routers 106-108, and a Radio NetworkController (“RNC”) 110. RNC 110 is further coupled with a Wide AreaNetwork (“WAN”) and/or Internet 150. Depending on the applications, RNC110 may be coupled with other RNC or RNCs to enhance network managementand capacities. Connections 130-132 are used to couple RNC 110 withrouters 106-108 wherein connections 130-132 can be wired linesconnections, wireless connections, or a combination of wired lines andwireless connections. It should be noted that the underlying concept ofthe exemplary embodiment(s) of the present invention would not change ifone or more blocks (or circuits) were added to or removed from diagram100.

Each router such as router 106 or 108, in one embodiment, is prioritizedin a sequential order wherein a router with the lower priority backs upa router with higher priority. A router with the highest priority is themaster router. Router priority, in one embodiment, is managed by a VRRPmessaging system. The VRRP is an object tracking system capable ofsystematically electing and/or assigning routing tasks to one or moreVRRP routers. A router using VRRP is also known as VRRP router. Theterms “router” and “VRRP router” are used interchangeably hereinafter.In a VRRP environment, a router is selected as a master router whileother routers are designated as a series of backup routers with apredefined order for backup the master router.

The routers such as routers 106-108 are interconnected by InteriorGateway Protocol (“IGP”) 118. Each router, for example, includesfunctions of IP routing. In one embodiment, a router such as router 106is capable of establishing a BFD session 140 directly to a host such ascell site 102 for monitoring connectivity between router 106 and cellsite 102 via switching network 104.

Switching network 104, as indicated in FIG. 1, is capable oftransporting information between circuit-based clients andpacket-switching clients. Switching network 104 can be an IP and/orMulti Protocol Label Switching (“MPLS”) based switching network whichmay operate at a layer of Open Systems Interconnection Basic ReferenceModel (“OSI model”). In one embodiment, network 104 includes a switchblock and a backhaul block used for transferring information and/orvarious data traffic to and from network clients. Network client in oneexample may include one or more routers, switches, hosts, base stations,and the like. Network 104 is capable of routing information between cellsites 102-103 and RNC 110 via routers 106-108. For example, while theswitch block of network 104 transmits information between cell site 102and router 106 via bus 116, the backhaul block of network 104 transmitsinformation between cells site 102 and router 108 via bus 114.

Cell site 102, also known as a base station, includes a radio tower 112,a computer 126, and a server 128, wherein radio tower 112 furtherincludes a cellular phone 120 and a handheld device 124 connected viawireless communications. Base station or cell site 102 is capable ofcommunicating with mobile devices such as cellular phone 120 andhandheld device 124 via radio tower 112. It should be noted that cellsite 102, not shown in FIG. 1, may include additional radio towers aswell as other land switching circuitry. The cell stations such as cellsites 102-103 can be configured to support wireless communications aswell as wired communications. Each cell site such as cell site 102 canbe considered as a host and it is capable of maintaining a connectivitysession such as a BFD session with a destination router for continuouslyverifying the connectivity between the host and the router.

BFD is a network connectivity protocol used to authenticate or detectfailures between two endpoints (i.e., a host and a master router). BFDis a short-duration for failure detection for path(s) between forwardingnetwork elements including interfaces, data links, forwarding planes,and forwarding engines. For example, a BFD session between a host and amaster router can be established over a network channel or link forverifying connectivity between the host and the master router. MultipleBFD sessions can also be formed if more than one network links existedbetween two endpoints. A session is failed or down if a BFD packet(s) isfailed to receive. It should be noted that, instead of using BFDsessions, other connectivity protocols can also be used. For example,Open Shortest Path First (“OSPF”), Intermediate System to IntermediateSystem (“IS-IS”), and/or any other protocols complying IEEE 802.1ag canbe used in place of BFD.

During an operation, one of the endpoints initiates an Echo function.Upon activation, Echo packets are sent by one of the endpoints. Uponreceipt of the Echo packets, the other endpoint subsequently sends theEcho packets back to the sender via a connectivity session such as a BFDsession. The connectivity between the two endpoints is failed if one ofthe endpoints does not receive the Echo packets.

As FIG. 1 illustrated, a host or cell site 102 is configured tocommunicate with a VRRP master router 106, wherein VRRP master router106 establishes a BFD session 140 with host 102. When BFD session 140fails, master router 106 sends VRRP messages to broadcast loweringmaster router's priority. For example, VRRP priority message declaresthat master router 106 has reduced its priority to the lowest priority.The lowering priority of master router 106 triggers and/or activates abackup VRRP router such as router 108 which becomes the new masterrouter and takes over the routing task from router 106. When BFD sessionis reestablished, the previous master router such as router 106broadcasts a VRRP message to raise the priority of router 106 from thelowest priority to the highest priority. Upon resetting the priority tothe highest, router 106 reassumes the master router status and takesover the routing tasks from its backup router 108.

An advantage of using BFD and VRRP tracking system is that when themaster router detects a failure of the BFD session, the master routerassumes that the data link such as bus 116 is down as well. The masterrouter such as router 106 uses the VRRP messaging system to activate orwake up the backup router such as router 108 to take over the routingtask. Router 108 takes over the routing task from router 106 whenpriority of router 108 is higher than the priority 106. As such, thedata traffic between cell site 102 and RNC 110 is not affected althoughthe router master has changed from router 106 to router 108.

FIG. 2 is a block diagram 200 illustrating an exemplary computer networkhaving multiple VRRP routers managed by BFD and VRRP in accordance withone embodiment of the present invention. Diagram 200 illustrates a basestation or cell site 102, VRRP routers 106-108, an RNC 110, and AccessGate switches (“AGS”) 210-214. AGS 210-214 are capable of performingswitch and/or router functions for routing network traffic includingvoice, data, and video information. It should be noted that theunderlying concept of the exemplary embodiment(s) of the presentinvention would not change if one or more blocks (circuit) were added toor removed from diagram 200.

Cell site 102, as discussed earlier, includes a radio tower(s),computers, servers, and the like. In one embodiment, a BFD session 220is established between router 106 and cell site 102 for connectivityverification. It should be noted that another BFD session, not shown inFIG. 2, may also be established between cell site 102 and router 108. Itshould be noted that BFD session 220 can travel through multiple devicessuch as AGS 210-212 before reaching cell site 102. BFD session 220continuously verifies the connectivity between cell site 102 and router106.

A VRRP tracking system 222, in one embodiment, is established betweenrouter 106 and router 108 via AGS 210-214. VRRP tracking system 222herein can also be referred to as VRRP tracking mechanism, VRRP network,VRRP messaging system, VRRP communication channels. System 222 iscapable of facilitating or issuing VRRP messages for assigning routerpriorities associated with traffic destinations. It should be noted thatit does not alter the underlying concept of the exemplary embodiments ifmore or less AGS are used to facilitate the VRRP message(s). While area204 can be view as the coupling area between the NB service interfaceand VRRP routers, area 206 illustrates a coupling area between RNC andVRRP routers. VRRP message controlled by VRRP tracking system 222 iscapable of providing the priority to routers 106-108.

The computer network, in one embodiment, supports and facilitatesvarious interfaces, such as IP Virtual Local Area Network (“VLAN”)interface, IP QinQ interface, IP Ethernet interface, and the like. Thesystem, for example, triggers a VRRP switch over from a master router toa backup router when the BFD session has been failed. The system shouldbe able to associate a BFD session with a VRRP virtual router.

BFD packets, in one example, are sequentially sent to an inband VirtualCircuit Connectivity Verification (“VCCV”) channel of a pseudowire(“PW”). VCCV BFD enhances the detection time of the connected/notconnected status of each PW across the network. It should be noted thatPW emulates native services such as ATM and Ethernet to a PacketSwitched Network (“PSN”) such as MPLS. The VCCV channel, in oneembodiment, can be utilized to handle BFD, wherein the BFD transmittedby the VCCV can provide early warning(s) indicating problems in anindividual PW across the network. It should be noted that the VCCV withthe BFD feature adds connectivity monitoring capability for PWs usingthe BFD mechanism.

During an operation, when BFD session 220 verifies normal connectivity,router 106, a master router, maintains data link(s) or data session(s)between cell site 102 and router 106. For a master router, it shouldhave a priority value of 255 which is the highest priority among theVRRP routers. When router 106 is the master router, router 106 isresponsible to route network traffic between cell site 102 and RNC 110.Router 106, for example, routes data over data paths 250-252, whereindata path 250 transports data stream from cell site 102 to RNC 110 anddata path 252 transports data stream from RNC 110 to cell site 102. Itshould be noted that other data paths may also be formed in connectionto router 106 but they are not important to understand the embodiment(s)of the present invention.

FIG. 3 is a block diagram 300 illustrating an exemplary process ofidentifying session failure by BFD in accordance with one embodiment ofthe present invention. Diagram 300, which is similar to diagram 200shown in FIG. 2, illustrates a host or base station 102, VRRP routers106-108, an RNC 110, and Access Gate switches (“AGS”) 210-214. AGS210-214 are capable of performing switch and/or router functions forrouting network traffic including voice, data, and video information. Itshould be noted that the underlying concept of the exemplaryembodiment(s) of the present invention would not change if one or moreblocks (circuit) were added to or removed from diagram 300.

Host 102 is coupled to VRRP routers 106-108. Master VRRP router 106maintains BFD session 220 with host 102. When BFD session 220 fails asindicated by a cross 306, master router 106 assumes and/or acknowledgesthat data link 238 is also down as indicated by a cross 302. Masterrouter 106 subsequently lowers its priority by sending a VRRP prioritymessage 308 with the lowest priority such as priority “0” over VRRPtracking mechanism 222. The VRRP priority message activates or wakes upa backup router such as router 108 to take over the routing tasks fromoriginal master router 106.

The priority for each VRRP router, for example, can be predefined with apriority sequence of “255” to “0” wherein priority “255” is the highestpriority and priority “0” is the lowest priority. If router 106 has apriority value of “255” and is the master router, router 108, forexample, may have a priority value of “200” and is assigned as a firstinline backup router 108 for the master router. Router 108, in oneembodiment, becomes the new master router when router 106 lowers itspriority value from “255” to “0” via VRRP tracking mechanism 222. Router106, however, can resume its status of master router by increasing itspriority value from “0” to “255” via VRRP tracking mechanism 222.

FIG. 4 is a diagram 400 illustrating an exemplary process of switchingrouting path upon detecting session failure in accordance with oneembodiment of the present invention. Diagram 400, which is similar todiagram 300 shown in FIG. 3, illustrates a host or base station 102,VRRP routers 106-108, an RNC 110, and Access Gate switches (“AGS”)210-214. It should be noted that the process illustrated in FIG. 4 is acontinuation process shown in FIG. 3. As illustrated in FIG. 3, originalmaster router 106 has lowered its priority value upon detecting BFDsession failure. It should be noted that the underlying concept of theexemplary embodiment(s) of the present invention would not change if oneor more blocks (circuit) were added to or removed from diagram 400.

Upon detecting the VRRP message indicating lowering priority value orlevel for the original master router 106, backup router 108 becomes thenew master router and takes over the routing task between host 102 andRNC 110 from the original master router 106. New data paths 450-452 areestablished in place of original data paths 250-252 between host 102 andRNC 110. Data path 450, for example, facilitates data transfer from RNC110 to host 102 via routers 106-108, AGS 210, and AGS 214. Data path452, on the other hand, transfers data from host 102 to RNC 110 viarouters 106-108, AGS 210, and AGS 214. Alternatively, data paths 450-452can also travel through connection 132 instead of connections 118 and130 to reach RNC 110. It should be noted that new master router 108 mayalso establish a BFD session between router 108 and host 102 forconnectivity verification between host 102 and router 108.

FIG. 5 is a diagram 500 illustrating an exemplary process of sessionrecovery in accordance with one embodiment of the present invention.Diagram 500, which is similar to diagram 400 shown in FIG. 4,illustrates a host or base station 102, VRRP routers 106-108, an RNC110, and Access Gate switches (“AGS”) 210-214. It should be noted thatthe process illustrated in FIG. 5 is a continuation process illustratedin FIG. 4. As shown in FIG. 4, original master router 106 has loweredits priority and router 108 has taken over the routing tasks betweenhost 102 and RNC 110. It should be noted that the underlying concept ofthe exemplary embodiment(s) of the present invention would not change ifone or more blocks (circuit) were added to or removed from diagram 500.

After acknowledging down links 220 and 238, router 106 tries to recoverand/or repair down links 220 and 238. When BFD session 220 and data link238 are recovered and re-established as indicated by numerals 502-506,original master router 106 reasserts its status as master router bysending a VRRP message assigning the highest priority to router 106 viaVRRP tracking mechanism 222. For example, upon recovering data link 238,router 106 issues a VRRP message raising the priority value from “0” to“255” for router 106 via VRRP tracking system 222. When router 108receives and acknowledges the new highest priority value carried by theVRRP message, router 108 releases its status as a master router. Router106 subsequently resumes its status as the master router and takes overthe routing tasks between host 102 and RNC 110 from router 108.

FIG. 6 is a diagram 600 illustrating an exemplary process of data linkrecovery in accordance with one embodiment of the present invention.Diagram 600, which is similar to diagram 500 shown in FIG. 5,illustrates a host or base station 102, VRRP routers 106-108, an RNC110, and Access Gate switches (“AGS”) 210-214. It should be noted thatthe process illustrated in FIG. 6 is a continuation process illustratedin FIG. 5. As shown in FIG. 5, original master router 106 has resumedits master router status after router 108 releases its master status andbecomes a backup router. It should be noted that the underlying conceptof the exemplary embodiment(s) of the present invention would not changeif one or more blocks (circuit) were added to or removed from diagram600.

Upon resumption of master status, router 106 establishes new data paths650-652 in place of backup data paths 450-452 between host 102 and RNC110. Alternatively, router 106 revives original data paths 250-252 asshown in FIG. 2 to facilitate data transfer between RNC 110 and host102. It should be noted that the switching from data paths 250-252 todata paths 450-452, shown in FIG. 4, and then switching back from datapaths 450-452 to data paths 650-652 shown in FIG. 6, are happed andfacilitated by routers 106-108 and AGS 210-214. In one embodiment, thenetwork performance between host 102 and RNC 110 is maintained duringthe switching process between the down links and backup links.

FIG. 7 is a block diagram 700 illustrating an exemplary network layouthaving multiple VRRP routers in accordance with one embodiment of thepresent invention. Diagram 700 includes routers 106-108 and a host orbase station 102 wherein routers 106-108 are connected to host 102 viaVLAN 1 and VLAN 2. Router 106, in one embodiment, establishes a BDF1session with IP address “10.10.10.1< >10.10.10.2” to host 102 whilerouter 108 establishes a BDF2 session with IP address“10.10.10.1< >10.10.10.3” to host 102. Host 102 can reach both routers106-108 via either VLAN1 or VLAN 2. For example, host 102 can use itsVLAN1 IP address “10.10.10.1” to reach IP addresses “10.10.10.2” and/or“10.10.10.3” wherein “10.10.10.2” is an IP address for router 106 and“10.10.10.3” is an IP address for router 108. Alternatively, host 102can use its VLAN2 IP address “10.10.11.1” to reach IP addresses“10.10.11.2” and/or “10.10.11.3” wherein “10.10.11.2” is an IP addressfor router 106 and “10.10.11.3” is an IP address for router 108.Connection 702, in one example, may be used for VRRP prioritymanagement. It should be noted that the underlying concept of theexemplary embodiment(s) of the present invention would not change if oneor more blocks (circuit) were added to or removed from diagram 700.

For configurable VRRP routers, one router is designated as a masterrouter and the rest of routers are backup routers. If a BFD session fora specific VRRP interface fails, master router such as router 106releases a VRRP priority message where priority of the master router isreset to “0” or some other configurable values indicating the lowestpriority among the VRRP routers. After VRRP master router lowers itspriority, one of the backup routers such as router 108 becomes a newmaster router. When a previously failed BFD session is reestablished,the original master router such as router 106 sends a VRRP messagedeclaring that router 106 has assigned with the highest priority(example VRRP priority of 255 or other configurable value) and hasresumed its status as the master router.

An advantage of employing BDF and VRRP tracking system is to offervarious network and application services over 3^(rd) party networks.With redundant routers and early detection of service failures, overallnetwork routing performance is enhanced.

The exemplary aspect of the present invention includes variousprocessing steps, which will be described below. The steps of the aspectmay be embodied in machine or computer executable instructions. Theinstructions can be used to cause a general purpose or special purposesystem, which is programmed with the instructions, to perform the stepsof the exemplary aspect of the present invention. Alternatively, thesteps of the exemplary aspect of the present invention may be performedby specific hardware components that contain hard-wired logic forperforming the steps, or by any combination of programmed computercomponents and custom hardware components.

FIG. 8 is a flowchart 800 illustrating a process capable of activating abackup router using a connectivity protocol in accordance with oneembodiment of the present invention. At block 802, a process of systemcommunication establishes a first data session between a host and afirst router. The first router has been assigned with a first priorityor priority value wherein the first priority is managed by a priorityprotocol. The process, in one embodiment, is capable of managing andprioritizing a group of routers via a VRRP or VRRP message. The process,in one example, facilitates to transfer information or data over anetwork session or data session between the host and the first router.

At block 804, the process forms a first connectivity session between thehost and the first router. For example, the process is capable ofsending a connectivity message for connectivity verification between thehost and the first router on a predefined time period. In oneembodiment, the process activates a BFD session for verifyingconnectivity between the host and the first router.

At block 806, the process lowers the first priority of the first routervia the priority protocol when the first connectivity session fails. Forexample, when a BFD session fails, the first router lowers its prioritywhereby a backup router (or a second router) can take over the routingtasks from the first router. The process, for example, is capable ofadjusting priority or priority level of the first router from thehighest priority to the lowest priority via VRRP.

At block 808, the process establishes a second data session between thehost and a second router. The second router, a backup router, isactivated to take over routing tasks from the first router. The secondrouter has a second priority managed by the priority protocol. A secondconnectivity session between the host and the second router can also beformed. The process is also able to repair and reestablish the firstconnectivity session between the host and the first router after thefirst connectivity session is down. Upon raising the first priority to ahighest priority when the first connectivity session is reestablished,the process resumes the first data session between the host and thefirst router once the highest priority of the first priority isaccomplished via the priority protocol.

While particular embodiments of the present invention have been shownand described, it will be obvious to those of skills in the art thatbased upon the teachings herein, changes and modifications may be madewithout departing from this exemplary embodiment(s) of the presentinvention and its broader aspects. Therefore, the appended claims areintended to encompass within their scope all such changes andmodifications as are within the true spirit and scope of this exemplaryembodiment(s) of the present invention.

1. A method for system communication, comprising: establishing a firstdata session between a host and a first router having a first prioritymanaged by a priority protocol; forming a first connectivity sessionbetween the host and the first router wherein the forming a firstconnectivity session includes sending a connectivity message between thehost and the first router on a predefined time period; lowering thefirst priority of the first router via the priority protocol when thefirst connectivity session fails; and establishing a second data sessionbetween the host and a second router having a second priority managed bythe priority protocol.
 2. The method of claim 1, further comprisingforming a second connectivity session between the host and the secondrouter.
 3. The method of claim 2, further comprising trying toreestablish the first connectivity session between the host and thefirst router.
 4. The method of claim 3, further comprising: raising thefirst priority to a highest priority when the first connectivity sessionis reestablished; and resuming the first data session between the hostand the first router once the highest priority of the first priority isaccomplished via the priority protocol.
 5. The method of claim 1,wherein the establishing a first data session between a host and a firstrouter having a first priority managed by a priority protocol includesmanaging and prioritizing a plurality of routers via a virtual routerredundancy protocol (“VRRP”).
 6. The method of claim 1, wherein forminga first connectivity session between the host and the first routerincludes activating a bidirectional forwarding detection (“BFD”) sessionfor verifying connectivity between the host and the first router.
 7. Themethod of claim 1, wherein lowering the first priority of the firstrouter via the priority protocol when the first connectivity sessionfails includes adjusting priority level of the first router from highestpriority to lowest priority via VRRP.
 8. The method of claim 1, whereinestablishing a first data session includes facilitating informationtransfer over a network session between the host and the first router.9. The method of claim 8, wherein establishing a second data sessionbetween the host and a second router having a second priority managed bythe priority protocol includes activating a backup router to take overrouting tasks from the first router.
 10. A method of systemcommunication, comprising: facilitating a first communication between ahost and a master router of a plurality of virtual router redundancyprotocol (“VRRP”) routers; establishing a first bidirectional forwardingdetection (“BFD”) session between the host and the master router;lowering priority levels of the master router when the first BFD sessionfails; and activating a backup router of the plurality of VRRP routersto perform functions of the master router.
 11. The method of claim 10,further comprising: facilitating a second communication between the hostand the backup router; and halting data transfer in the firstcommunication.
 12. The method of claim 11, further comprising:increasing priority levels of the master router when the first BFDsession resumes; and halting data transfer in the second communication.13. The method of claim 12, further comprising resuming data transfer inthe first communication.
 14. The method of claim 10, wherein loweringpriority levels of the master router further includes establishing apriority messaging system utilizing VRRP to prioritize the plurality ofVRRP routers.
 15. The method of claim 10, wherein establishing a firstbidirectional forwarding detection (“BFD”) session includes monitoringnetwork connectivity between the host and the master router.
 16. Themethod of claim 10, wherein lowering priority levels of the masterrouter when the first BFD session fails includes broadcasting a lowestpriority level associated to the master router via a VRRP message. 17.The method of claim 10, wherein activating a backup router of theplurality of VRRP routers to perform functions of the master routerincludes establishing a second BFD session between the host and thebackup router.
 18. A network system, comprising: a base stationconfigured to communicate with wireless devices; a first router coupledwith the base station via a data bus and configured to transport datapackets via the data bus; a bidirectional forwarding detection (“BFD”)session coupled with the base station and the first router andconfigured to verifying connectivity between the base station and thefirst router; and a second router coupled with the first router andconfigured to communicate with the first router via virtual routerredundancy protocol (“VRRP”), wherein the second router takes overrouting tasks from the first router when the BFD session fails.
 19. Thenetwork system of claim 18, wherein the first router is a VRRP routerand is capable of adjusting its priority level in response toconnectivity of the BFD.
 20. The network system of claim 19, wherein thefirst router is a master router and the second router is a backup routermanaged by the VRRP.